56% have gone months without replacing your mascara.

Why it's a beauty crime Experts say that the lifespan of mascara is three months max. So if your tube is older than that (which, based on our survey, we're going to guess it is), you're putting yourself at risk for red, itchy eyes and conjunctivitis. Not pretty.

56% have gone months without replacing your mascara.

Change your ways Clean up your act: Replace tubes to prevent bacteria buildup. And turn the wand in circular motions—don't pump it in and out, Perdis says; doing this also prevents the formula from drying by keeping excess air out.

55% of you admit to going to sleep with makeup on.

Why it's a beauty crime Going to bed without cleansing skin can clog pores, causing breakouts and also making pores larger. "When you're sleeping, you're lying on skin, so makeup is pushed deeper into pores and, over time, can stretch them out," explains Dennis Gross, M.D., a dermatologist in NYC.

55% of you admit to going to sleep with makeup on.

Change your ways Fortunately, beauty aisles are flooded with facial wipes you can use in a flash. Look for towelettes that don't require rinsing, have healthy-skin ingredients such as aloe vera (try Yes to Cucumbers facial towelettes, 30 for $6) and hydrate while they cleanse.

53% never remember to wash your makeup brushes.

Why it's a beauty crime Most brushes are made of synthetic bristles that don't build up bacteria. But a makeup-saturated brush can muddy colors. "If you're using one brush for bronzer and pink blush, and you don't wash your brushes, you won't get the true shades you want," Surratt says.

Hit the right (blush) spot every time with the tapered Sonia Kashuk Blusher Brush, $18.

53% never remember to wash your makeup brushes.

Change your ways Use your fingers to apply most of your makeup if you don't have time to wash your brushes. If you do suds them up, use warm water and a mild wash such as Aveda Shampure Shampoo, $11, monthly. Then air-dry brushes by laying them flat on a towel.